mcs/anonymous.cs

   1 //
   2 // anonymous.cs: Support for anonymous methods and types
   3 //
   4 // Author:
   5 //   Miguel de Icaza (miguel@ximain.com)
   6 //   Marek Safar (marek.safar@gmail.com)
   7 //
   8 // Dual licensed under the terms of the MIT X11 or GNU GPL
   9 // Copyright 2003-2008 Novell, Inc.
  10 //
  11
  12 using System;
  13 using System.Text;
  14 using System.Collections;
  15 using System.Collections.Specialized;
  16 using System.Reflection;
  17 using System.Reflection.Emit;
  18
  19 namespace Mono.CSharp {
  20
  21         public abstract class CompilerGeneratedClass : Class
  22         {
  23                 public static string MakeName (string host, string typePrefix, string name, int id)
  24                 {
  25                         return "<" + host + ">" + typePrefix + "__" + name + id.ToString ("X");
  26                 }
  27
  28                 protected CompilerGeneratedClass (DeclSpace parent, MemberName name, int mod)
  29                         : base (parent.NamespaceEntry, parent, name, mod | Modifiers.COMPILER_GENERATED | Modifiers.SEALED, null)
  30                 {
  31                 }
  32
  33                 protected CompilerGeneratedClass (DeclSpace parent, GenericMethod generic, MemberName name, int mod)
  34                         : this (parent, name, mod)
  35                 {
  36                         if (generic != null) {
  37                                 ArrayList list = new ArrayList ();
  38                                 foreach (TypeParameter tparam in generic.TypeParameters) {
  39                                         if (tparam.Constraints != null)
  40                                                 list.Add (tparam.Constraints.Clone ());
  41                                 }
  42                                 SetParameterInfo (list);
  43                         }
  44                 }
  45
  46                 protected void CheckMembersDefined ()
  47                 {
  48                         if (members_defined)
  49                                 throw new InternalErrorException ("Helper class already defined!");
  50                 }
  51         }
  52
  53         //
  54         // Anonymous method storey is created when an anonymous method uses
  55         // variable or parameter from outer scope. They are then hoisted to
  56         // anonymous method storey (captured)
  57         //
  58         public class AnonymousMethodStorey : CompilerGeneratedClass
  59         {
  60                 class StoreyFieldPair {
  61                         public readonly AnonymousMethodStorey Storey;
  62                         public readonly Field Field;
  63
  64                         public StoreyFieldPair (AnonymousMethodStorey storey, Field field)
  65                         {
  66                                 this.Storey = storey;
  67                                 this.Field = field;
  68                         }
  69
  70                         public override int GetHashCode ()
  71                         {
  72                                 return Storey.ID.GetHashCode ();
  73                         }
  74
  75                         public override bool Equals (object obj)
  76                         {
  77                                 return (AnonymousMethodStorey)obj == Storey;
  78                         }
  79                 }
  80
  81                 sealed class HoistedGenericField : Field
  82                 {
  83                         public HoistedGenericField (DeclSpace parent, FullNamedExpression type, int mod, string name,
  84                                   Attributes attrs, Location loc)
  85                                 : base (parent, type, mod, new MemberName (name, loc), attrs)
  86                         {
  87                         }
  88
  89                         protected override bool ResolveMemberType ()
  90                         {
  91                                 if (!base.ResolveMemberType ())
  92                                         return false;
  93
  94                                 AnonymousMethodStorey parent = ((AnonymousMethodStorey) Parent).GetGenericStorey ();
  95                                 if (parent != null)
  96                                         member_type = parent.MutateType (member_type);
  97
  98                                 return true;
  99                         }
 100                 }
 101
 102                 //
 103                 // Needed to delay hoisted _this_ initialization. When an anonymous
 104                 // method is used inside ctor and _this_ is hoisted, base ctor has to
 105                 // be called first, otherwise _this_ will be initialized with
 106                 // uninitialized value.
 107                 //
 108                 sealed class ThisInitializer : Statement
 109                 {
 110                         readonly HoistedThis hoisted_this;
 111
 112                         public ThisInitializer (HoistedThis hoisted_this)
 113                         {
 114                                 this.hoisted_this = hoisted_this;
 115                         }
 116
 117                         protected override void DoEmit (EmitContext ec)
 118                         {
 119                                 hoisted_this.EmitHoistingAssignment (ec);
 120                         }
 121
 122                         protected override void CloneTo (CloneContext clonectx, Statement target)
 123                         {
 124                                 // Nothing to clone
 125                         }
 126
 127                         public override void MutateHoistedGenericType (AnonymousMethodStorey storey)
 128                         {
 129                                 // Nothing to mutate
 130                         }
 131                 }
 132
 133                 // Unique storey ID
 134                 public readonly int ID;
 135                 static int unique_id;
 136
 137                 public readonly Block OriginalSourceBlock;
 138
 139                 // A list of StoreyFieldPair with local field keeping parent storey instance
 140                 ArrayList used_parent_storeys;
 141                 ArrayList children_references;
 142
 143                 // A list of hoisted parameters
 144                 protected ArrayList hoisted_params;
 145                 protected ArrayList hoisted_locals;
 146
 147                 // Hoisted this
 148                 protected HoistedThis hoisted_this;
 149
 150                 // Local variable which holds this storey instance
 151                 public LocalTemporary Instance;
 152
 153                 public AnonymousMethodStorey (Block block, DeclSpace parent, MemberBase host, GenericMethod generic, string name)
 154                         : base (parent, generic, MakeMemberName (host, name, generic, block.StartLocation), Modifiers.PRIVATE)
 155                 {
 156                         Parent = parent;
 157                         OriginalSourceBlock = block;
 158                         ID = unique_id++;
 159                 }
 160
 161                 static MemberName MakeMemberName (MemberBase host, string name, GenericMethod generic, Location loc)
 162                 {
 163                         string host_name = host == null ? null : host.Name;
 164                         string tname = MakeName (host_name, "c", name, unique_id);
 165                         TypeArguments args = null;
 166                         if (generic != null) {
 167                                 args = new TypeArguments ();
 168                                 foreach (TypeParameter tparam in generic.CurrentTypeParameters)
 169                                         args.Add (new TypeParameterName (tparam.Name, null, loc));
 170                         }
 171
 172                         return new MemberName (tname, args, loc);
 173                 }
 174
 175                 public void AddCapturedThisField (EmitContext ec)
 176                 {
 177                         TypeExpr type_expr = new TypeExpression (ec.ContainerType, Location);
 178                         Field f = AddCompilerGeneratedField ("<>f__this", type_expr);
 179                         f.Define ();
 180                         hoisted_this = new HoistedThis (this, f);
 181                 }
 182
 183                 public Field AddCapturedVariable (string name, Type type)
 184                 {
 185                         CheckMembersDefined ();
 186
 187                         FullNamedExpression field_type = new TypeExpression (type, Location);
 188                         if (!IsGeneric)
 189                                 return AddCompilerGeneratedField (name, field_type);
 190
 191                         const int mod = Modifiers.INTERNAL | Modifiers.COMPILER_GENERATED;
 192                         Field f = new HoistedGenericField (this, field_type, mod, name, null, Location);
 193                         AddField (f);
 194                         return f;
 195                 }
 196
 197                 protected Field AddCompilerGeneratedField (string name, FullNamedExpression type)
 198                 {
 199                         const int mod = Modifiers.INTERNAL | Modifiers.COMPILER_GENERATED;
 200                         Field f = new Field (this, type, mod, new MemberName (name, Location), null);
 201                         AddField (f);
 202                         return f;
 203                 }
 204
 205                 //
 206                 // Creates a link between block and the anonymous method storey
 207                 //
 208                 // An anonymous method can reference variables from any outer block, but they are
 209                 // hoisted in their own ExplicitBlock. When more than one block is referenced we
 210                 // need to create another link between those variable storeys
 211                 //
 212                 public void AddReferenceFromChildrenBlock (ExplicitBlock block)
 213                 {
 214                         if (children_references == null)
 215                                 children_references = new ArrayList ();
 216
 217                         if (!children_references.Contains (block))
 218                                 children_references.Add (block);
 219                 }
 220
 221                 public void AddParentStoreyReference (AnonymousMethodStorey storey)
 222                 {
 223                         CheckMembersDefined ();
 224
 225                         if (used_parent_storeys == null)
 226                                 used_parent_storeys = new ArrayList ();
 227                         else if (used_parent_storeys.IndexOf (storey) != -1)
 228                                 return;
 229
 230                         TypeExpr type_expr = new TypeExpression (storey.TypeBuilder, Location);
 231                         Field f = AddCompilerGeneratedField ("<>f__ref$" + storey.ID, type_expr);
 232                         used_parent_storeys.Add (new StoreyFieldPair (storey, f));
 233                 }
 234
 235                 public void CaptureLocalVariable (EmitContext ec, LocalInfo local_info)
 236                 {
 237                         ec.CurrentBlock.Explicit.HasCapturedVariable = true;
 238                         if (ec.CurrentBlock.Explicit != local_info.Block.Explicit)
 239                                 AddReferenceFromChildrenBlock (ec.CurrentBlock.Explicit);
 240
 241                         if (local_info.HoistedVariableReference != null)
 242                                 return;
 243
 244                         HoistedVariable var = new HoistedLocalVariable (this, local_info, GetVariableMangledName (local_info));
 245                         local_info.HoistedVariableReference = var;
 246
 247                         if (hoisted_locals == null)
 248                                 hoisted_locals = new ArrayList ();
 249
 250                         hoisted_locals.Add (var);
 251                 }
 252
 253                 public void CaptureParameter (EmitContext ec, ParameterReference param_ref)
 254                 {
 255                         ec.CurrentBlock.Explicit.HasCapturedVariable = true;
 256                         AddReferenceFromChildrenBlock (ec.CurrentBlock.Explicit);
 257
 258                         if (param_ref.GetHoistedVariable (ec) != null)
 259                                 return;
 260
 261                         if (hoisted_params == null)
 262                                 hoisted_params = new ArrayList (2);
 263
 264                         HoistedVariable expr = new HoistedParameter (this, param_ref);
 265                         param_ref.Parameter.HoistedVariableReference = expr;
 266                         hoisted_params.Add (expr);
 267                 }
 268
 269                 public void ChangeParentStorey (AnonymousMethodStorey parentStorey)
 270                 {
 271                         Parent = parentStorey;
 272                         type_params = null;
 273                 }
 274
 275                 //
 276                 // Initializes all hoisted variables
 277                 //
 278                 public void EmitStoreyInstantiation (EmitContext ec)
 279                 {
 280                         // There can be only one instance variable for each storey type
 281                         if (Instance != null)
 282                                 throw new InternalErrorException ();
 283
 284                         SymbolWriter.OpenCompilerGeneratedBlock (ec.ig);
 285
 286                         //
 287                         // Create an instance of storey type
 288                         //
 289                         Expression storey_type_expr;
 290                         if (is_generic) {
 291                                 //
 292                                 // Use current method type parameter (MVAR) for top level storey only. All
 293                                 // nested storeys use class type parameter (VAR)
 294                                 //
 295                                 TypeParameter[] tparams = ec.CurrentAnonymousMethod != null && ec.CurrentAnonymousMethod.Storey != null ?
 296                                         ec.CurrentAnonymousMethod.Storey.TypeParameters :
 297                                         ec.GenericDeclContainer.TypeParameters;
 298
 299                                 TypeArguments targs = new TypeArguments ();
 300
 301                                 if (tparams.Length < CountTypeParameters) {
 302                                         TypeParameter[] parent_tparams = ec.DeclContainer.Parent.PartialContainer.TypeParameters;
 303                                         for (int i = 0; i < parent_tparams.Length; ++i)
 304                                                 targs.Add (new TypeParameterExpr (parent_tparams[i], Location));
 305                                 }
 306
 307                                 for (int i = 0; i < tparams.Length; ++i)
 308                                         targs.Add (new TypeParameterExpr (tparams[i], Location));
 309
 310                                 storey_type_expr = new GenericTypeExpr (TypeBuilder, targs, Location);
 311                         } else {
 312                                 storey_type_expr = new TypeExpression (TypeBuilder, Location);
 313                         }
 314
 315                         Expression e = new New (storey_type_expr, null, Location).Resolve (ec);
 316                         e.Emit (ec);
 317
 318                         Instance = new LocalTemporary (storey_type_expr.Type);
 319                         Instance.Store (ec);
 320
 321                         EmitHoistedFieldsInitialization (ec);
 322
 323                         SymbolWriter.DefineScopeVariable (ID, Instance.Builder);
 324                         SymbolWriter.CloseCompilerGeneratedBlock (ec.ig);
 325                 }
 326
 327                 void EmitHoistedFieldsInitialization (EmitContext ec)
 328                 {
 329                         //
 330                         // Initialize all storey reference fields by using local or hoisted variables
 331                         //
 332                         if (used_parent_storeys != null) {
 333                                 foreach (StoreyFieldPair sf in used_parent_storeys) {
 334                                         //
 335                                         // Setting local field
 336                                         //
 337                                         Expression instace_expr = GetStoreyInstanceExpression (ec);
 338                                         FieldExpr f_set_expr = TypeManager.IsGenericType (instace_expr.Type) ?
 339                                                 new FieldExpr (sf.Field.FieldBuilder, instace_expr.Type, Location) :
 340                                                 new FieldExpr (sf.Field.FieldBuilder, Location);
 341                                         f_set_expr.InstanceExpression = instace_expr;
 342
 343                                         SimpleAssign a = new SimpleAssign (f_set_expr, sf.Storey.GetStoreyInstanceExpression (ec));
 344                                         if (a.Resolve (ec) != null)
 345                                                 a.EmitStatement (ec);
 346                                 }
 347                         }
 348
 349                         //
 350                         // Define hoisted `this' in top-level storey only
 351                         //
 352                         if (OriginalSourceBlock.Explicit.HasCapturedThis && !(Parent is AnonymousMethodStorey)) {
 353                                 AddCapturedThisField (ec);
 354                                 OriginalSourceBlock.AddScopeStatement (new ThisInitializer (hoisted_this));
 355                         }
 356
 357                         //
 358                         // Setting currect anonymous method to null blocks any further variable hoisting
 359                         //
 360                         AnonymousExpression ae = ec.CurrentAnonymousMethod;
 361                         ec.CurrentAnonymousMethod = null;
 362
 363                         if (hoisted_params != null) {
 364                                 EmitHoistedParameters (ec, hoisted_params);
 365                         }
 366
 367                         ec.CurrentAnonymousMethod = ae;
 368                 }
 369
 370                 protected virtual void EmitHoistedParameters (EmitContext ec, ArrayList hoisted)
 371                 {
 372                         foreach (HoistedParameter hp in hoisted) {
 373                                 hp.EmitHoistingAssignment (ec);
 374                         }
 375                 }
 376
 377                 public override void EmitType ()
 378                 {
 379                         SymbolWriter.DefineAnonymousScope (ID);
 380
 381                         if (hoisted_this != null)
 382                                 hoisted_this.EmitSymbolInfo ();
 383
 384                         if (hoisted_locals != null) {
 385                                 foreach (HoistedVariable local in hoisted_locals)
 386                                         local.EmitSymbolInfo ();
 387                         }
 388
 389                         if (hoisted_params != null) {
 390                                 foreach (HoistedParameter param in hoisted_params)
 391                                         param.EmitSymbolInfo ();
 392                         }
 393
 394                         if (used_parent_storeys != null) {
 395                                 foreach (StoreyFieldPair sf in used_parent_storeys) {
 396                                         SymbolWriter.DefineCapturedScope (ID, sf.Storey.ID, sf.Field.Name);
 397                                 }
 398                         }
 399
 400                         base.EmitType ();
 401                 }
 402
 403                 public AnonymousMethodStorey GetGenericStorey ()
 404                 {
 405                         DeclSpace storey = this;
 406                         while (storey != null && storey.CurrentTypeParameters.Length == 0)
 407                                 storey = storey.Parent;
 408
 409                         return storey as AnonymousMethodStorey;
 410                 }
 411
 412                 //
 413                 // Returns a field which holds referenced storey instance
 414                 //
 415                 Field GetReferencedStoreyField (AnonymousMethodStorey storey)
 416                 {
 417                         if (used_parent_storeys == null)
 418                                 return null;
 419
 420                         foreach (StoreyFieldPair sf in used_parent_storeys) {
 421                                 if (sf.Storey == storey)
 422                                         return sf.Field;
 423                         }
 424
 425                         return null;
 426                 }
 427
 428                 //
 429                 // Creates storey instance expression regardless of currect IP
 430                 //
 431                 public Expression GetStoreyInstanceExpression (EmitContext ec)
 432                 {
 433                         AnonymousExpression am = ec.CurrentAnonymousMethod;
 434
 435                         //
 436                         // Access from original block -> storey
 437                         //
 438                         if (am == null)
 439                                 return Instance;
 440
 441                         //
 442                         // Access from anonymous method implemented as a static -> storey
 443                         //
 444                         if (am.Storey == null)
 445                                 return Instance;
 446
 447                         Field f = am.Storey.GetReferencedStoreyField (this);
 448                         if (f == null) {
 449                                 if (am.Storey == this) {
 450                                         //
 451                                         // Access inside of same storey (S -> S)
 452                                         //
 453                                         return new CompilerGeneratedThis (TypeBuilder, Location);
 454                                 }
 455                                 //
 456                                 // External field access
 457                                 //
 458                                 return Instance;
 459                         }
 460
 461                         //
 462                         // Storey was cached to local field
 463                         //
 464                         FieldExpr f_ind = new FieldExpr (f.FieldBuilder, Location);
 465                         f_ind.InstanceExpression = new CompilerGeneratedThis (TypeBuilder, Location);
 466                         return f_ind;
 467                 }
 468
 469                 protected virtual string GetVariableMangledName (LocalInfo local_info)
 470                 {
 471                         //
 472                         // No need to mangle anonymous method hoisted variables cause they
 473                         // are hoisted in their own scopes
 474                         //
 475                         return local_info.Name;
 476                 }
 477
 478                 public HoistedThis HoistedThis {
 479                         get { return hoisted_this; }
 480                 }
 481
 482                 //
 483                 // Mutate type dispatcher
 484                 //
 485                 public Type MutateType (Type type)
 486                 {
 487 #if GMCS_SOURCE
 488                         if (TypeManager.IsGenericType (type))
 489                                 return MutateGenericType (type);
 490
 491                         if (TypeManager.IsGenericParameter (type))
 492                                 return MutateGenericArgument (type);
 493
 494                         if (type.IsArray)
 495                                 return MutateArrayType (type);
 496 #endif
 497                         return type;
 498                 }
 499
 500                 //
 501                 // Changes method type arguments (MVAR) to storey (VAR) type arguments
 502                 //
 503                 public MethodInfo MutateGenericMethod (MethodInfo method)
 504                 {
 505 #if GMCS_SOURCE
 506                         Type [] t_args = TypeManager.GetGenericArguments (method);
 507                         if (TypeManager.IsGenericType (method.DeclaringType)) {
 508                                 Type t = MutateGenericType (method.DeclaringType);
 509                                 if (t != method.DeclaringType) {
 510                                         method = (MethodInfo) TypeManager.DropGenericMethodArguments (method);
 511                                         if (method.Module == Module.Builder)
 512                                                 method = TypeBuilder.GetMethod (t, method);
 513                                         else
 514                                                 method = (MethodInfo) MethodInfo.GetMethodFromHandle (method.MethodHandle, t.TypeHandle);
 515                                 }
 516                         }
 517
 518                         if (t_args == null || t_args.Length == 0)
 519                                 return method;
 520
 521                         for (int i = 0; i < t_args.Length; ++i)
 522                                 t_args [i] = MutateType (t_args [i]);
 523
 524                         return method.GetGenericMethodDefinition ().MakeGenericMethod (t_args);
 525 #else
 526                         throw new NotSupportedException ();
 527 #endif
 528                 }
 529
 530                 public ConstructorInfo MutateConstructor (ConstructorInfo ctor)
 531                 {
 532 #if GMCS_SOURCE
 533                         if (TypeManager.IsGenericType (ctor.DeclaringType)) {
 534                                 Type t = MutateGenericType (ctor.DeclaringType);
 535                                 if (t != ctor.DeclaringType) {
 536                                         ctor = (ConstructorInfo) TypeManager.DropGenericMethodArguments (ctor);
 537                                         if (ctor.Module == Module.Builder)
 538                                                 return TypeBuilder.GetConstructor (t, ctor);
 539
 540                                         return (ConstructorInfo) ConstructorInfo.GetMethodFromHandle (ctor.MethodHandle, t.TypeHandle);
 541                                 }
 542                         }
 543 #endif
 544                         return ctor;
 545                 }
 546
 547                 public FieldInfo MutateField (FieldInfo field)
 548                 {
 549 #if GMCS_SOURCE
 550                         if (TypeManager.IsGenericType (field.DeclaringType)) {
 551                                 Type t = MutateGenericType (field.DeclaringType);
 552                                 if (t != field.DeclaringType) {
 553                                         field = TypeManager.DropGenericTypeArguments (field.DeclaringType).GetField (field.Name, TypeManager.AllMembers);
 554                                         if (field.Module == Module.Builder)
 555                                                 return TypeBuilder.GetField (t, field);
 556
 557                                         return FieldInfo.GetFieldFromHandle (field.FieldHandle, t.TypeHandle);
 558                                 }
 559                         }
 560 #endif
 561                         return field;
 562                 }
 563
 564 #if GMCS_SOURCE
 565                 protected Type MutateArrayType (Type array)
 566                 {
 567                         Type element = TypeManager.GetElementType (array);
 568                         if (element.IsArray) {
 569                                 element = MutateArrayType (element);
 570                         } else if (TypeManager.IsGenericParameter (element)) {
 571                                 element = MutateGenericArgument (element);
 572                         } else if (TypeManager.IsGenericType (element)) {
 573                                 element = MutateGenericType (element);
 574                         } else {
 575                                 return array;
 576                         }
 577
 578                         int rank = array.GetArrayRank ();
 579                         if (rank == 1)
 580                                 return element.MakeArrayType ();
 581
 582                         return element.MakeArrayType (rank);
 583                 }
 584
 585                 protected Type MutateGenericType (Type type)
 586                 {
 587                         Type [] t_args = TypeManager.GetTypeArguments (type);
 588                         if (t_args == null || t_args.Length == 0)
 589                                 return type;
 590
 591                         for (int i = 0; i < t_args.Length; ++i)
 592                                 t_args [i] = MutateType (t_args [i]);
 593
 594                         return TypeManager.DropGenericTypeArguments (type).MakeGenericType (t_args);
 595                 }
 596 #endif
 597
 598                 //
 599                 // Changes method generic argument (MVAR) to type generic argument (VAR)
 600                 //
 601                 public Type MutateGenericArgument (Type type)
 602                 {
 603                         foreach (TypeParameter tp in CurrentTypeParameters) {
 604                                 if (tp.Name == type.Name) {
 605                                         return tp.Type;
 606                                 }
 607                         }
 608
 609                         return type;
 610                 }
 611
 612                 public ArrayList ReferencesFromChildrenBlock {
 613                         get { return children_references; }
 614                 }
 615
 616                 public static void Reset ()
 617                 {
 618                         unique_id = 0;
 619                 }
 620         }
 621
 622         public abstract class HoistedVariable
 623         {
 624                 class ExpressionTreeProxy : Expression
 625                 {
 626                         readonly HoistedVariable hv;
 627
 628                         public ExpressionTreeProxy (HoistedVariable hv)
 629                         {
 630                                 this.hv = hv;
 631                         }
 632
 633                         public override Expression CreateExpressionTree (EmitContext ec)
 634                         {
 635                                 throw new NotSupportedException ("ET");
 636                         }
 637
 638                         public override Expression DoResolve (EmitContext ec)
 639                         {
 640                                 eclass = ExprClass.Value;
 641                                 type = TypeManager.expression_type_expr.Type;
 642                                 return this;
 643                         }
 644
 645                         public override void Emit (EmitContext ec)
 646                         {
 647                                 Expression e = hv.GetFieldExpression (ec).CreateExpressionTree (ec);
 648                                 // This should never fail
 649                                 e = e.Resolve (ec);
 650                                 if (e != null)
 651                                         e.Emit (ec);
 652                         }
 653                 }
 654
 655                 protected readonly AnonymousMethodStorey storey;
 656                 protected Field field;
 657                 Hashtable cached_inner_access; // TODO: Hashtable is too heavyweight
 658                 FieldExpr cached_outer_access;
 659
 660                 protected HoistedVariable (AnonymousMethodStorey storey, string name, Type type)
 661                         : this (storey, storey.AddCapturedVariable (name, type))
 662                 {
 663                 }
 664
 665                 protected HoistedVariable (AnonymousMethodStorey storey, Field field)
 666                 {
 667                         this.storey = storey;
 668                         this.field = field;
 669                 }
 670
 671                 public void AddressOf (EmitContext ec, AddressOp mode)
 672                 {
 673                         GetFieldExpression (ec).AddressOf (ec, mode);
 674                 }
 675
 676                 public Expression CreateExpressionTree (EmitContext ec)
 677                 {
 678                         return new ExpressionTreeProxy (this);
 679                 }
 680
 681                 public void Emit (EmitContext ec)
 682                 {
 683                         GetFieldExpression (ec).Emit (ec);
 684                 }
 685
 686                 //
 687                 // Creates field access expression for hoisted variable
 688                 //
 689                 protected FieldExpr GetFieldExpression (EmitContext ec)
 690                 {
 691                         if (ec.CurrentAnonymousMethod == null || ec.CurrentAnonymousMethod.Storey == null) {
 692                                 if (cached_outer_access != null)
 693                                         return cached_outer_access;
 694
 695                                 //
 696                                 // When setting top-level hoisted variable in generic storey
 697                                 // change storey generic types to method generic types (VAR -> MVAR)
 698                                 //
 699                                 cached_outer_access = storey.MemberName.IsGeneric ?
 700                                         new FieldExpr (field.FieldBuilder, storey.Instance.Type, field.Location) :
 701                                         new FieldExpr (field.FieldBuilder, field.Location);
 702
 703                                 cached_outer_access.InstanceExpression = storey.GetStoreyInstanceExpression (ec);
 704                                 cached_outer_access.Resolve (ec);
 705                                 return cached_outer_access;
 706                         }
 707
 708                         FieldExpr inner_access;
 709                         if (cached_inner_access != null) {
 710                                 inner_access = (FieldExpr) cached_inner_access [ec.CurrentAnonymousMethod];
 711                         } else {
 712                                 inner_access = null;
 713                                 cached_inner_access = new Hashtable (4);
 714                         }
 715
 716                         if (inner_access == null) {
 717 // TODO: It should be something like this to work correctly with expression trees
 718 //                              inner_access = ec.CurrentAnonymousMethod.Storey != storey && storey.MemberName.IsGeneric ?
 719 //                                      new FieldExpr (field.FieldBuilder, storey.Instance.Type, field.Location) :
 720 //                                      new FieldExpr (field.FieldBuilder, field.Location);
 721
 722                                 inner_access = new FieldExpr (field.FieldBuilder, field.Location);
 723                                 inner_access.InstanceExpression = storey.GetStoreyInstanceExpression (ec);
 724                                 inner_access.Resolve (ec);
 725                                 cached_inner_access.Add (ec.CurrentAnonymousMethod, inner_access);
 726                         }
 727
 728                         return inner_access;
 729                 }
 730
 731                 public abstract void EmitSymbolInfo ();
 732
 733                 public void Emit (EmitContext ec, bool leave_copy)
 734                 {
 735                         GetFieldExpression (ec).Emit (ec, leave_copy);
 736                 }
 737
 738                 public void EmitAssign (EmitContext ec, Expression source, bool leave_copy, bool prepare_for_load)
 739                 {
 740                         GetFieldExpression (ec).EmitAssign (ec, source, leave_copy, false);
 741                 }
 742         }
 743
 744         class HoistedParameter : HoistedVariable
 745         {
 746                 sealed class HoistedFieldAssign : Assign
 747                 {
 748                         public HoistedFieldAssign (Expression target, Expression source)
 749                                 : base (target, source, source.Location)
 750                         {
 751                         }
 752
 753                         protected override Expression ResolveConversions (EmitContext ec)
 754                         {
 755                                 //
 756                                 // Implicit conversion check fails for hoisted type arguments
 757                                 // as they are of different types (!!0 x !0)
 758                                 //
 759                                 return this;
 760                         }
 761                 }
 762
 763                 readonly ParameterReference parameter;
 764
 765                 public HoistedParameter (AnonymousMethodStorey scope, ParameterReference par)
 766                         : base (scope, par.Name, par.Type)
 767                 {
 768                         this.parameter = par;
 769                 }
 770
 771                 public HoistedParameter (HoistedParameter hp, string name)
 772                         : base (hp.storey, name, hp.parameter.Type)
 773                 {
 774                         this.parameter = hp.parameter;
 775                 }
 776
 777                 public void EmitHoistingAssignment (EmitContext ec)
 778                 {
 779                         //
 780                         // Remove hoisted redirection to emit assignment from original parameter
 781                         //
 782                         HoistedVariable temp = parameter.Parameter.HoistedVariableReference;
 783                         parameter.Parameter.HoistedVariableReference = null;
 784
 785                         Assign a = new HoistedFieldAssign (GetFieldExpression (ec), parameter);
 786                         if (a.Resolve (ec) != null)
 787                                 a.EmitStatement (ec);
 788
 789                         parameter.Parameter.HoistedVariableReference = temp;
 790                 }
 791
 792                 public override void EmitSymbolInfo ()
 793                 {
 794                         SymbolWriter.DefineCapturedParameter (storey.ID, field.Name, field.Name);
 795                 }
 796
 797                 public Field Field {
 798                         get { return field; }
 799                 }
 800         }
 801
 802         class HoistedLocalVariable : HoistedVariable
 803         {
 804                 readonly string name;
 805
 806                 public HoistedLocalVariable (AnonymousMethodStorey scope, LocalInfo local, string name)
 807                         : base (scope, name, local.VariableType)
 808                 {
 809                         this.name = local.Name;
 810                 }
 811
 812                 public override void EmitSymbolInfo ()
 813                 {
 814                         SymbolWriter.DefineCapturedLocal (storey.ID, name, field.Name);
 815                 }
 816         }
 817
 818         public class HoistedThis : HoistedVariable
 819         {
 820                 public HoistedThis (AnonymousMethodStorey storey, Field field)
 821                         : base (storey, field)
 822                 {
 823                 }
 824
 825                 public void EmitHoistingAssignment (EmitContext ec)
 826                 {
 827                         SimpleAssign a = new SimpleAssign (GetFieldExpression (ec), ec.GetThis (field.Location));
 828                         if (a.Resolve (ec) != null)
 829                                 a.EmitStatement (ec);
 830                 }
 831
 832                 public override void EmitSymbolInfo ()
 833                 {
 834                         SymbolWriter.DefineCapturedThis (storey.ID, field.Name);
 835                 }
 836
 837                 public Field Field {
 838                         get { return field; }
 839                 }
 840         }
 841
 842         //
 843         // Anonymous method expression as created by parser
 844         //
 845         public class AnonymousMethodExpression : Expression
 846         {
 847                 ListDictionary compatibles;
 848                 public ToplevelBlock Block;
 849
 850                 public AnonymousMethodExpression (Location loc)
 851                 {
 852                         this.loc = loc;
 853                         this.compatibles = new ListDictionary ();
 854                 }
 855
 856                 public override string ExprClassName {
 857                         get {
 858                                 return "anonymous method";
 859                         }
 860                 }
 861
 862                 public virtual bool HasExplicitParameters {
 863                         get {
 864                                 return Parameters != ParametersCompiled.Undefined;
 865                         }
 866                 }
 867
 868                 public ParametersCompiled Parameters {
 869                         get { return Block.Parameters; }
 870                 }
 871
 872                 //
 873                 // Returns true if the body of lambda expression can be implicitly
 874                 // converted to the delegate of type `delegate_type'
 875                 //
 876                 public bool ImplicitStandardConversionExists (EmitContext ec, Type delegate_type)
 877                 {
 878                         using (ec.With (EmitContext.Flags.InferReturnType, false)) {
 879                                 using (ec.Set (EmitContext.Flags.ProbingMode)) {
 880                                         return Compatible (ec, delegate_type) != null;
 881                                 }
 882                         }
 883                 }
 884
 885                 protected Type CompatibleChecks (EmitContext ec, Type delegate_type)
 886                 {
 887                         if (TypeManager.IsDelegateType (delegate_type))
 888                                 return delegate_type;
 889
 890                         if (TypeManager.DropGenericTypeArguments (delegate_type) == TypeManager.expression_type) {
 891                                 delegate_type = TypeManager.GetTypeArguments (delegate_type) [0];
 892                                 if (TypeManager.IsDelegateType (delegate_type))
 893                                         return delegate_type;
 894
 895                                 Report.Error (835, loc, "Cannot convert `{0}' to an expression tree of non-delegate type `{1}'",
 896                                         GetSignatureForError (), TypeManager.CSharpName (delegate_type));
 897                                 return null;
 898                         }
 899
 900                         Report.Error (1660, loc, "Cannot convert `{0}' to non-delegate type `{1}'",
 901                                       GetSignatureForError (), TypeManager.CSharpName (delegate_type));
 902                         return null;
 903                 }
 904
 905                 protected bool VerifyExplicitParameters (Type delegate_type, AParametersCollection parameters, bool ignore_error)
 906                 {
 907                         if (VerifyParameterCompatibility (delegate_type, parameters, ignore_error))
 908                                 return true;
 909
 910                         if (!ignore_error)
 911                                 Report.Error (1661, loc,
 912                                         "Cannot convert `{0}' to delegate type `{1}' since there is a parameter mismatch",
 913                                         GetSignatureForError (), TypeManager.CSharpName (delegate_type));
 914
 915                         return false;
 916                 }
 917
 918                 protected bool VerifyParameterCompatibility (Type delegate_type, AParametersCollection invoke_pd, bool ignore_errors)
 919                 {
 920                         if (Parameters.Count != invoke_pd.Count) {
 921                                 if (ignore_errors)
 922                                         return false;
 923
 924                                 Report.Error (1593, loc, "Delegate `{0}' does not take `{1}' arguments",
 925                                               TypeManager.CSharpName (delegate_type), Parameters.Count.ToString ());
 926                                 return false;
 927                         }
 928
 929                         bool has_implicit_parameters = !HasExplicitParameters;
 930                         bool error = false;
 931
 932                         for (int i = 0; i < Parameters.Count; ++i) {
 933                                 Parameter.Modifier p_mod = invoke_pd.FixedParameters [i].ModFlags;
 934                                 if (Parameters.FixedParameters [i].ModFlags != p_mod && p_mod != Parameter.Modifier.PARAMS) {
 935                                         if (ignore_errors)
 936                                                 return false;
 937
 938                                         if (p_mod == Parameter.Modifier.NONE)
 939                                                 Report.Error (1677, loc, "Parameter `{0}' should not be declared with the `{1}' keyword",
 940                                                               (i + 1).ToString (), Parameter.GetModifierSignature (Parameters.FixedParameters [i].ModFlags));
 941                                         else
 942                                                 Report.Error (1676, loc, "Parameter `{0}' must be declared with the `{1}' keyword",
 943                                                               (i+1).ToString (), Parameter.GetModifierSignature (p_mod));
 944                                         error = true;
 945                                 }
 946
 947                                 if (has_implicit_parameters)
 948                                         continue;
 949
 950                                 Type type = invoke_pd.Types [i];
 951
 952                                 // We assume that generic parameters are always inflated
 953                                 if (TypeManager.IsGenericParameter (type))
 954                                         continue;
 955
 956                                 if (TypeManager.HasElementType (type) && TypeManager.IsGenericParameter (TypeManager.GetElementType (type)))
 957                                         continue;
 958
 959                                 if (invoke_pd.Types [i] != Parameters.Types [i]) {
 960                                         if (ignore_errors)
 961                                                 return false;
 962
 963                                         Report.Error (1678, loc, "Parameter `{0}' is declared as type `{1}' but should be `{2}'",
 964                                                       (i+1).ToString (),
 965                                                       TypeManager.CSharpName (Parameters.Types [i]),
 966                                                       TypeManager.CSharpName (invoke_pd.Types [i]));
 967                                         error = true;
 968                                 }
 969                         }
 970
 971                         return !error;
 972                 }
 973
 974                 //
 975                 // Infers type arguments based on explicit arguments
 976                 //
 977                 public bool ExplicitTypeInference (TypeInferenceContext type_inference, Type delegate_type)
 978                 {
 979                         if (!HasExplicitParameters)
 980                                 return false;
 981
 982                         if (!TypeManager.IsDelegateType (delegate_type)) {
 983                                 if (TypeManager.DropGenericTypeArguments (delegate_type) != TypeManager.expression_type)
 984                                         return false;
 985
 986                                 delegate_type = TypeManager.GetTypeArguments (delegate_type) [0];
 987                                 if (!TypeManager.IsDelegateType (delegate_type))
 988                                         return false;
 989                         }
 990
 991                         AParametersCollection d_params = TypeManager.GetDelegateParameters (delegate_type);
 992                         if (d_params.Count != Parameters.Count)
 993                                 return false;
 994
 995                         for (int i = 0; i < Parameters.Count; ++i) {
 996                                 Type itype = d_params.Types [i];
 997                                 if (!TypeManager.IsGenericParameter (itype)) {
 998                                         if (!TypeManager.HasElementType (itype))
 999                                                 continue;
1000
1001                                         if (!TypeManager.IsGenericParameter (TypeManager.GetElementType (itype)))
1002                                             continue;
1003                                 }
1004                                 type_inference.ExactInference (Parameters.Types [i], itype);
1005                         }
1006                         return true;
1007                 }
1008
1009                 public Type InferReturnType (EmitContext ec, TypeInferenceContext tic, Type delegate_type)
1010                 {
1011                         AnonymousMethodBody am;
1012                         using (ec.Set (EmitContext.Flags.ProbingMode | EmitContext.Flags.InferReturnType)) {
1013                                 am = CompatibleMethod (ec, tic, TypeManager.null_type, delegate_type);
1014                         }
1015
1016                         if (am == null)
1017                                 return null;
1018
1019                         // Stop referencing gmcs NullLiteral type
1020                         if (am.ReturnType == TypeManager.null_type)
1021                                 am.ReturnType = null;
1022
1023                         return am.ReturnType;
1024                 }
1025
1026                 //
1027                 // Returns AnonymousMethod container if this anonymous method
1028                 // expression can be implicitly converted to the delegate type `delegate_type'
1029                 //
1030                 public Expression Compatible (EmitContext ec, Type type)
1031                 {
1032                         Expression am = (Expression) compatibles [type];
1033                         if (am != null)
1034                                 return am;
1035
1036                         Type delegate_type = CompatibleChecks (ec, type);
1037                         if (delegate_type == null)
1038                                 return null;
1039
1040                         //
1041                         // At this point its the first time we know the return type that is
1042                         // needed for the anonymous method.  We create the method here.
1043                         //
1044
1045                         MethodInfo invoke_mb = Delegate.GetInvokeMethod (
1046                                 ec.ContainerType, delegate_type);
1047                         Type return_type = TypeManager.TypeToCoreType (invoke_mb.ReturnType);
1048
1049 #if MS_COMPATIBLE
1050                         Type[] g_args = delegate_type.GetGenericArguments ();
1051                         if (return_type.IsGenericParameter)
1052                                 return_type = g_args [return_type.GenericParameterPosition];
1053 #endif
1054
1055                         //
1056                         // Second: the return type of the delegate must be compatible with
1057                         // the anonymous type.   Instead of doing a pass to examine the block
1058                         // we satisfy the rule by setting the return type on the EmitContext
1059                         // to be the delegate type return type.
1060                         //
1061
1062                         try {
1063                                 int errors = Report.Errors;
1064                                 am = CompatibleMethod (ec, null, return_type, delegate_type);
1065                                 if (am != null && delegate_type != type && errors == Report.Errors)
1066                                         am = CreateExpressionTree (ec, delegate_type);
1067
1068                                 if (!ec.IsInProbingMode)
1069                                         compatibles.Add (type, am == null ? EmptyExpression.Null : am);
1070
1071                                 return am;
1072                         } catch (CompletionResult){
1073                                 throw;
1074                         } catch (Exception e) {
1075                                 throw new InternalErrorException (e, loc);
1076                         }
1077                 }
1078
1079                 protected virtual Expression CreateExpressionTree (EmitContext ec, Type delegate_type)
1080                 {
1081                         return CreateExpressionTree (ec);
1082                 }
1083
1084                 public override Expression CreateExpressionTree (EmitContext ec)
1085                 {
1086                         Report.Error (1946, loc, "An anonymous method cannot be converted to an expression tree");
1087                         return null;
1088                 }
1089
1090                 protected virtual ParametersCompiled ResolveParameters (EmitContext ec, TypeInferenceContext tic, Type delegate_type)
1091                 {
1092                         AParametersCollection delegate_parameters = TypeManager.GetDelegateParameters (delegate_type);
1093
1094                         if (Parameters == ParametersCompiled.Undefined) {
1095                                 //
1096                                 // We provide a set of inaccessible parameters
1097                                 //
1098                                 Parameter[] fixedpars = new Parameter[delegate_parameters.Count];
1099
1100                                 for (int i = 0; i < delegate_parameters.Count; i++) {
1101                                         Parameter.Modifier i_mod = delegate_parameters.FixedParameters [i].ModFlags;
1102                                         if (i_mod == Parameter.Modifier.OUT) {
1103                                                 Report.Error (1688, loc, "Cannot convert anonymous " +
1104                                                                   "method block without a parameter list " +
1105                                                                   "to delegate type `{0}' because it has " +
1106                                                                   "one or more `out' parameters.",
1107                                                                   TypeManager.CSharpName (delegate_type));
1108                                                 return null;
1109                                         }
1110                                         fixedpars[i] = new Parameter (
1111                                                 null, null,
1112                                                 delegate_parameters.FixedParameters [i].ModFlags, null, loc);
1113                                 }
1114
1115                                 return ParametersCompiled.CreateFullyResolved (fixedpars, delegate_parameters.Types);
1116                         }
1117
1118                         if (!VerifyExplicitParameters (delegate_type, delegate_parameters, ec.IsInProbingMode)) {
1119                                 return null;
1120                         }
1121
1122                         return Parameters;
1123                 }
1124
1125                 public override Expression DoResolve (EmitContext ec)
1126                 {
1127                         if (!ec.IsAnonymousMethodAllowed) {
1128                                 Report.Error (1706, loc, "Anonymous methods and lambda expressions cannot be used in the current context");
1129                                 return null;
1130                         }
1131
1132                         //
1133                         // Set class type, set type
1134                         //
1135
1136                         eclass = ExprClass.Value;
1137
1138                         //
1139                         // This hack means `The type is not accessible
1140                         // anywhere', we depend on special conversion
1141                         // rules.
1142                         //
1143                         type = InternalType.AnonymousMethod;
1144
1145                         if ((Parameters != null) && !Parameters.Resolve (ec))
1146                                 return null;
1147
1148                         // FIXME: The emitted code isn't very careful about reachability
1149                         // so, ensure we have a 'ret' at the end
1150                         if (ec.CurrentBranching != null &&
1151                             ec.CurrentBranching.CurrentUsageVector.IsUnreachable)
1152                                 ec.NeedReturnLabel ();
1153
1154                         return this;
1155                 }
1156
1157                 public override void Emit (EmitContext ec)
1158                 {
1159                         // nothing, as we only exist to not do anything.
1160                 }
1161
1162                 public static void Error_AddressOfCapturedVar (IVariableReference var, Location loc)
1163                 {
1164                         Report.Error (1686, loc,
1165                                 "Local variable or parameter `{0}' cannot have their address taken and be used inside an anonymous method or lambda expression",
1166                                 var.Name);
1167                 }
1168
1169                 public override string GetSignatureForError ()
1170                 {
1171                         return ExprClassName;
1172                 }
1173
1174                 protected AnonymousMethodBody CompatibleMethod (EmitContext ec, TypeInferenceContext tic, Type return_type, Type delegate_type)
1175                 {
1176                         ParametersCompiled p = ResolveParameters (ec, tic, delegate_type);
1177                         if (p == null)
1178                                 return null;
1179
1180                         ToplevelBlock b = ec.IsInProbingMode ? (ToplevelBlock) Block.PerformClone () : Block;
1181
1182                         AnonymousMethodBody anonymous = CompatibleMethodFactory (return_type, delegate_type, p, b);
1183                         if (!anonymous.Compatible (ec))
1184                                 return null;
1185
1186                         return anonymous;
1187                 }
1188
1189                 protected virtual AnonymousMethodBody CompatibleMethodFactory (Type return_type, Type delegate_type, ParametersCompiled p, ToplevelBlock b)
1190                 {
1191                         return new AnonymousMethodBody (p, b, return_type, delegate_type, loc);
1192                 }
1193
1194                 protected override void CloneTo (CloneContext clonectx, Expression t)
1195                 {
1196                         AnonymousMethodExpression target = (AnonymousMethodExpression) t;
1197
1198                         target.Block = (ToplevelBlock) clonectx.LookupBlock (Block);
1199                 }
1200         }
1201
1202         //
1203         // Abstract expression for any block which requires variables hoisting
1204         //
1205         public abstract class AnonymousExpression : Expression
1206         {
1207                 protected class AnonymousMethodMethod : Method
1208                 {
1209                         public readonly AnonymousExpression AnonymousMethod;
1210                         public readonly AnonymousMethodStorey Storey;
1211                         readonly string RealName;
1212
1213                         public AnonymousMethodMethod (DeclSpace parent, AnonymousExpression am, AnonymousMethodStorey storey,
1214                                                           GenericMethod generic, TypeExpr return_type,
1215                                                           int mod, string real_name, MemberName name,
1216                                                           ParametersCompiled parameters)
1217                                 : base (parent, generic, return_type, mod | Modifiers.COMPILER_GENERATED,
1218                                                 name, parameters, null)
1219                         {
1220                                 this.AnonymousMethod = am;
1221                                 this.Storey = storey;
1222                                 this.RealName = real_name;
1223
1224                                 Parent.PartialContainer.AddMethod (this);
1225                                 Block = am.Block;
1226                         }
1227
1228                         public override EmitContext CreateEmitContext (DeclSpace tc, ILGenerator ig)
1229                         {
1230                                 EmitContext aec = AnonymousMethod.aec;
1231                                 aec.ig = ig;
1232                                 aec.IsStatic = (ModFlags & Modifiers.STATIC) != 0;
1233                                 return aec;
1234                         }
1235
1236                         protected override bool ResolveMemberType ()
1237                         {
1238                                 if (!base.ResolveMemberType ())
1239                                         return false;
1240
1241                                 if (Storey != null && Storey.IsGeneric) {
1242                                         AnonymousMethodStorey gstorey = Storey.GetGenericStorey ();
1243                                         if (gstorey != null) {
1244                                                 if (!Parameters.IsEmpty) {
1245                                                         Type [] ptypes = Parameters.Types;
1246                                                         for (int i = 0; i < ptypes.Length; ++i)
1247                                                                 ptypes [i] = gstorey.MutateType (ptypes [i]);
1248                                                 }
1249
1250                                                 member_type = gstorey.MutateType (member_type);
1251                                         }
1252                                 }
1253
1254                                 return true;
1255                         }
1256
1257                         public override void Emit ()
1258                         {
1259                                 //
1260                                 // Before emitting any code we have to change all MVAR references to VAR
1261                                 // when the method is of generic type and has hoisted variables
1262                                 //
1263                                 if (Storey == Parent && Storey.IsGeneric) {
1264                                         AnonymousMethodStorey gstorey = Storey.GetGenericStorey ();
1265                                         if (gstorey != null) {
1266                                                 AnonymousMethod.aec.ReturnType = gstorey.MutateType (ReturnType);
1267                                                 block.MutateHoistedGenericType (gstorey);
1268                                         }
1269                                 }
1270
1271                                 if (MethodBuilder == null) {
1272                                         Define ();
1273                                 }
1274
1275                                 base.Emit ();
1276                         }
1277
1278                         public override void EmitExtraSymbolInfo (SourceMethod source)
1279                         {
1280                                 source.SetRealMethodName (RealName);
1281                         }
1282                 }
1283
1284                 //
1285                 // The block that makes up the body for the anonymous method
1286                 //
1287                 protected readonly ToplevelBlock Block;
1288
1289                 public Type ReturnType;
1290                 protected EmitContext aec;
1291
1292                 protected AnonymousExpression (ToplevelBlock block, Type return_type, Location loc)
1293                 {
1294                         this.ReturnType = return_type;
1295                         this.Block = block;
1296                         this.loc = loc;
1297                 }
1298
1299                 public abstract string ContainerType { get; }
1300                 public abstract bool IsIterator { get; }
1301                 public abstract AnonymousMethodStorey Storey { get; }
1302
1303                 public bool Compatible (EmitContext ec)
1304                 {
1305                         // TODO: Implement clone
1306                         aec = new EmitContext (
1307                                 ec.ResolveContext, ec.TypeContainer, ec.DeclContainer,
1308                                 Location, null, ReturnType,
1309                                 (ec.InUnsafe ? Modifiers.UNSAFE : 0), /* No constructor */ false);
1310
1311                         aec.CurrentAnonymousMethod = this;
1312                         aec.IsStatic = ec.IsStatic;
1313
1314                         IDisposable aec_dispose = null;
1315                         EmitContext.Flags flags = 0;
1316                         if (ec.InferReturnType)
1317                                 flags |= EmitContext.Flags.InferReturnType;
1318
1319                         if (ec.IsInProbingMode)
1320                                 flags |= EmitContext.Flags.ProbingMode;
1321
1322                         if (ec.IsInFieldInitializer)
1323                                 flags |= EmitContext.Flags.InFieldInitializer;
1324
1325                         if (ec.IsInUnsafeScope)
1326                                 flags |= EmitContext.Flags.InUnsafe;
1327
1328                         // HACK: Flag with 0 cannot be set
1329                         if (flags != 0)
1330                                 aec_dispose = aec.Set (flags);
1331
1332                         bool unreachable;
1333                         bool res = aec.ResolveTopBlock (ec, Block, Block.Parameters, null, out unreachable);
1334
1335                         if (ec.InferReturnType)
1336                                 ReturnType = aec.ReturnType;
1337
1338                         if (aec_dispose != null) {
1339                                 aec_dispose.Dispose ();
1340                         }
1341
1342                         return res;
1343                 }
1344
1345                 public void SetHasThisAccess ()
1346                 {
1347                         Block.HasCapturedThis = true;
1348                         ExplicitBlock b = Block.Parent.Explicit;
1349
1350                         while (b != null) {
1351                                 if (b.HasCapturedThis)
1352                                         return;
1353
1354                                 b.HasCapturedThis = true;
1355                                 b = b.Parent == null ? null : b.Parent.Explicit;
1356                         }
1357                 }
1358         }
1359
1360         public class AnonymousMethodBody : AnonymousExpression
1361         {
1362                 protected readonly ParametersCompiled parameters;
1363                 AnonymousMethodStorey storey;
1364
1365                 AnonymousMethodMethod method;
1366                 Field am_cache;
1367
1368                 static int unique_id;
1369
1370                 public AnonymousMethodBody (ParametersCompiled parameters,
1371                                         ToplevelBlock block, Type return_type, Type delegate_type,
1372                                         Location loc)
1373                         : base (block, return_type, loc)
1374                 {
1375                         this.type = delegate_type;
1376                         this.parameters = parameters;
1377                 }
1378
1379                 public override string ContainerType {
1380                         get { return "anonymous method"; }
1381                 }
1382
1383                 public override AnonymousMethodStorey Storey {
1384                         get { return storey; }
1385                 }
1386
1387                 public override bool IsIterator {
1388                         get { return false; }
1389                 }
1390
1391                 public override Expression CreateExpressionTree (EmitContext ec)
1392                 {
1393                         Report.Error (1945, loc, "An expression tree cannot contain an anonymous method expression");
1394                         return null;
1395                 }
1396
1397                 bool Define (EmitContext ec)
1398                 {
1399                         if (aec == null && !Compatible (ec))
1400                                 return false;
1401
1402                         return true;
1403                 }
1404
1405                 //
1406                 // Creates a host for the anonymous method
1407                 //
1408                 AnonymousMethodMethod DoCreateMethodHost (EmitContext ec)
1409                 {
1410                         //
1411                         // Anonymous method body can be converted to
1412                         //
1413                         // 1, an instance method in current scope when only `this' is hoisted
1414                         // 2, a static method in current scope when neither `this' nor any variable is hoisted
1415                         // 3, an instance method in compiler generated storey when any hoisted variable exists
1416                         //
1417
1418                         int modifiers;
1419                         if (Block.HasCapturedVariable || Block.HasCapturedThis) {
1420                                 storey = FindBestMethodStorey ();
1421                                 modifiers = storey != null ? Modifiers.INTERNAL : Modifiers.PRIVATE;
1422                         } else {
1423                                 if (ec.CurrentAnonymousMethod != null)
1424                                         storey = ec.CurrentAnonymousMethod.Storey;
1425
1426                                 modifiers = Modifiers.STATIC | Modifiers.PRIVATE;
1427                         }
1428
1429                         DeclSpace parent = storey != null ? storey : ec.TypeContainer;
1430
1431                         MemberCore mc = ec.ResolveContext as MemberCore;
1432                         string name = CompilerGeneratedClass.MakeName (parent != storey ? mc.Name : null,
1433                                 "m", null, unique_id++);
1434
1435                         MemberName member_name;
1436                         GenericMethod generic_method;
1437                         if (storey == null && mc.MemberName.IsGeneric) {
1438                                 member_name = new MemberName (name, mc.MemberName.TypeArguments.Clone (), Location);
1439
1440                                 generic_method = new GenericMethod (parent.NamespaceEntry, parent, member_name,
1441                                         new TypeExpression (ReturnType, Location), parameters);
1442
1443                                 ArrayList list = new ArrayList ();
1444                                 foreach (TypeParameter tparam in ((IMethodData)mc).GenericMethod.CurrentTypeParameters) {
1445                                         if (tparam.Constraints != null)
1446                                                 list.Add (tparam.Constraints.Clone ());
1447                                 }
1448                                 generic_method.SetParameterInfo (list);
1449                         } else {
1450                                 member_name = new MemberName (name, Location);
1451                                 generic_method = null;
1452                         }
1453
1454                         string real_name = String.Format (
1455                                 "{0}~{1}{2}", mc.GetSignatureForError (), GetSignatureForError (),
1456                                 parameters.GetSignatureForError ());
1457
1458                         return new AnonymousMethodMethod (parent,
1459                                 this, storey, generic_method, new TypeExpression (ReturnType, Location), modifiers,
1460                                 real_name, member_name, parameters);
1461                 }
1462
1463                 public override Expression DoResolve (EmitContext ec)
1464                 {
1465                         if (eclass == ExprClass.Invalid) {
1466                                 if (!Define (ec))
1467                                         return null;
1468                         }
1469
1470                         eclass = ExprClass.Value;
1471                         return this;
1472                 }
1473
1474                 public override void Emit (EmitContext ec)
1475                 {
1476                         //
1477                         // Use same anonymous method implementation for scenarios where same
1478                         // code is used from multiple blocks, e.g. field initializers
1479                         //
1480                         if (method == null) {
1481                                 //
1482                                 // Delay an anonymous method definition to avoid emitting unused code
1483                                 // for unreachable blocks or expression trees
1484                                 //
1485                                 method = DoCreateMethodHost (ec);
1486                                 method.Define ();
1487                         }
1488
1489                         bool is_static = (method.ModFlags & Modifiers.STATIC) != 0;
1490                         if (is_static && am_cache == null) {
1491                                 //
1492                                 // Creates a field cache to store delegate instance if it's not generic
1493                                 //
1494                                 if (!method.MemberName.IsGeneric) {
1495                                         TypeContainer parent = method.Parent.PartialContainer;
1496                                         int id = parent.Fields == null ? 0 : parent.Fields.Count;
1497                                         am_cache = new Field (parent, new TypeExpression (type, loc),
1498                                                 Modifiers.STATIC | Modifiers.PRIVATE | Modifiers.COMPILER_GENERATED,
1499                                                 new MemberName (CompilerGeneratedClass.MakeName (null, "f", "am$cache", id), loc), null);
1500                                         am_cache.Define ();
1501                                         parent.AddField (am_cache);
1502                                 } else {
1503                                         // TODO: Implement caching of generated generic static methods
1504                                         //
1505                                         // Idea:
1506                                         //
1507                                         // Some extra class is needed to capture variable generic type
1508                                         // arguments. Maybe we could re-use anonymous types, with a unique
1509                                         // anonymous method id, but they are quite heavy.
1510                                         //
1511                                         // Consider : "() => typeof(T);"
1512                                         //
1513                                         // We need something like
1514                                         // static class Wrap<Tn, Tm, DelegateType> {
1515                                         //              public static DelegateType cache;
1516                                         // }
1517                                         //
1518                                         // We then specialize local variable to capture all generic parameters
1519                                         // and delegate type, e.g. "Wrap<Ta, Tb, DelegateTypeInst> cache;"
1520                                         //
1521                                 }
1522                         }
1523
1524                         ILGenerator ig = ec.ig;
1525                         Label l_initialized = ig.DefineLabel ();
1526
1527                         if (am_cache != null) {
1528                                 ig.Emit (OpCodes.Ldsfld, am_cache.FieldBuilder);
1529                                 ig.Emit (OpCodes.Brtrue_S, l_initialized);
1530                         }
1531
1532                         //
1533                         // Load method delegate implementation
1534                         //
1535
1536                         if (is_static) {
1537                                 ig.Emit (OpCodes.Ldnull);
1538                         } else if (storey != null) {
1539                                 Expression e = storey.GetStoreyInstanceExpression (ec).Resolve (ec);
1540                                 if (e != null)
1541                                         e.Emit (ec);
1542                         } else {
1543                                 ig.Emit (OpCodes.Ldarg_0);
1544                         }
1545
1546                         MethodInfo delegate_method = method.MethodBuilder;
1547                         if (storey != null && storey.MemberName.IsGeneric) {
1548                                 Type t = storey.Instance.Type;
1549
1550                                 //
1551                                 // Mutate anonymous method instance type if we are in nested
1552                                 // hoisted generic anonymous method storey
1553                                 //
1554                                 if (ec.CurrentAnonymousMethod != null &&
1555                                         ec.CurrentAnonymousMethod.Storey != null &&
1556                                         ec.CurrentAnonymousMethod.Storey.IsGeneric) {
1557                                         t = storey.GetGenericStorey ().MutateType (t);
1558                                 }
1559
1560 #if GMCS_SOURCE
1561                                 delegate_method = TypeBuilder.GetMethod (t, delegate_method);
1562 #else
1563                                 throw new NotSupportedException ();
1564 #endif
1565                         }
1566
1567                         ig.Emit (OpCodes.Ldftn, delegate_method);
1568
1569                         ConstructorInfo constructor_method = Delegate.GetConstructor (ec.ContainerType, type);
1570 #if MS_COMPATIBLE
1571             if (type.IsGenericType && type is TypeBuilder)
1572                 constructor_method = TypeBuilder.GetConstructor (type, constructor_method);
1573 #endif
1574                         ig.Emit (OpCodes.Newobj, constructor_method);
1575
1576                         if (am_cache != null) {
1577                                 ig.Emit (OpCodes.Stsfld, am_cache.FieldBuilder);
1578                                 ig.MarkLabel (l_initialized);
1579                                 ig.Emit (OpCodes.Ldsfld, am_cache.FieldBuilder);
1580                         }
1581                 }
1582
1583                 //
1584                 // Look for the best storey for this anonymous method
1585                 //
1586                 AnonymousMethodStorey FindBestMethodStorey ()
1587                 {
1588                         //
1589                         // Use the nearest parent block which has a storey
1590                         //
1591                         for (Block b = Block.Parent; b != null; b = b.Parent) {
1592                                 AnonymousMethodStorey s = b.Explicit.AnonymousMethodStorey;
1593                                 if (s != null)
1594                                         return s;
1595                         }
1596
1597                         return null;
1598                 }
1599
1600                 public override string GetSignatureForError ()
1601                 {
1602                         return TypeManager.CSharpName (type);
1603                 }
1604
1605                 public override void MutateHoistedGenericType (AnonymousMethodStorey storey)
1606                 {
1607                         type = storey.MutateType (type);
1608                 }
1609
1610                 public static void Reset ()
1611                 {
1612                         unique_id = 0;
1613                 }
1614         }
1615
1616         //
1617         // Anonymous type container
1618         //
1619         public class AnonymousTypeClass : CompilerGeneratedClass
1620         {
1621                 sealed class AnonymousParameters : ParametersCompiled
1622                 {
1623                         public AnonymousParameters (params Parameter[] parameters)
1624                                 : base (parameters)
1625                         {
1626                         }
1627
1628                         protected override void ErrorDuplicateName (Parameter p)
1629                         {
1630                                 Report.Error (833, p.Location, "`{0}': An anonymous type cannot have multiple properties with the same name",
1631                                         p.Name);
1632                         }
1633                 }
1634
1635                 static int types_counter;
1636                 public const string ClassNamePrefix = "<>__AnonType";
1637                 public const string SignatureForError = "anonymous type";
1638
1639                 readonly ArrayList parameters;
1640
1641                 private AnonymousTypeClass (DeclSpace parent, MemberName name, ArrayList parameters, Location loc)
1642                         : base (parent, name, (RootContext.EvalMode ? Modifiers.PUBLIC : 0) | Modifiers.SEALED)
1643                 {
1644                         this.parameters = parameters;
1645                 }
1646
1647                 public static AnonymousTypeClass Create (TypeContainer parent, ArrayList parameters, Location loc)
1648                 {
1649                         if (RootContext.MetadataCompatibilityVersion < MetadataVersion.v2)
1650                                 Report.FeatureIsNotSupported (loc, "anonymous types");
1651
1652                         string name = ClassNamePrefix + types_counter++;
1653
1654                         SimpleName [] t_args = new SimpleName [parameters.Count];
1655                         TypeParameterName [] t_params = new TypeParameterName [parameters.Count];
1656                         Parameter [] ctor_params = new Parameter [parameters.Count];
1657                         for (int i = 0; i < parameters.Count; ++i) {
1658                                 AnonymousTypeParameter p = (AnonymousTypeParameter) parameters [i];
1659
1660                                 t_args [i] = new SimpleName ("<" + p.Name + ">__T", p.Location);
1661                                 t_params [i] = new TypeParameterName (t_args [i].Name, null, p.Location);
1662                                 ctor_params [i] = new Parameter (t_args [i], p.Name, 0, null, p.Location);
1663                         }
1664
1665                         //
1666                         // Create generic anonymous type host with generic arguments
1667                         // named upon properties names
1668                         //
1669                         AnonymousTypeClass a_type = new AnonymousTypeClass (parent.NamespaceEntry.SlaveDeclSpace,
1670                                 new MemberName (name, new TypeArguments (t_params), loc), parameters, loc);
1671
1672                         if (parameters.Count > 0)
1673                                 a_type.SetParameterInfo (null);
1674
1675                         Constructor c = new Constructor (a_type, name, Modifiers.PUBLIC | Modifiers.DEBUGGER_HIDDEN,
1676                                 null, new AnonymousParameters (ctor_params), null, loc);
1677                         c.Block = new ToplevelBlock (c.Parameters, loc);
1678
1679                         //
1680                         // Create fields and contructor body with field initialization
1681                         //
1682                         bool error = false;
1683                         for (int i = 0; i < parameters.Count; ++i) {
1684                                 AnonymousTypeParameter p = (AnonymousTypeParameter) parameters [i];
1685
1686                                 Field f = new Field (a_type, t_args [i], Modifiers.PRIVATE | Modifiers.READONLY,
1687                                         new MemberName ("<" + p.Name + ">", p.Location), null);
1688
1689                                 if (!a_type.AddField (f)) {
1690                                         error = true;
1691                                         continue;
1692                                 }
1693
1694                                 c.Block.AddStatement (new StatementExpression (
1695                                         new SimpleAssign (new MemberAccess (new This (p.Location), f.Name),
1696                                                 c.Block.GetParameterReference (p.Name, p.Location))));
1697
1698                                 ToplevelBlock get_block = new ToplevelBlock (p.Location);
1699                                 get_block.AddStatement (new Return (
1700                                         new MemberAccess (new This (p.Location), f.Name), p.Location));
1701                                 Accessor get_accessor = new Accessor (get_block, 0, null, null, p.Location);
1702                                 Property prop = new Property (a_type, t_args [i], Modifiers.PUBLIC,
1703                                         new MemberName (p.Name, p.Location), null, get_accessor, null, false);
1704                                 a_type.AddProperty (prop);
1705                         }
1706
1707                         if (error)
1708                                 return null;
1709
1710                         a_type.AddConstructor (c);
1711                         return a_type;
1712                 }
1713
1714                 public static void Reset ()
1715                 {
1716                         types_counter = 0;
1717                 }
1718
1719                 protected override bool AddToContainer (MemberCore symbol, string name)
1720                 {
1721                         MemberCore mc = (MemberCore) defined_names [name];
1722
1723                         if (mc == null) {
1724                                 defined_names.Add (name, symbol);
1725                                 return true;
1726                         }
1727
1728                         Report.SymbolRelatedToPreviousError (mc);
1729                         return false;
1730                 }
1731
1732                 void DefineOverrides ()
1733                 {
1734                         Location loc = Location;
1735
1736                         Method equals = new Method (this, null, TypeManager.system_boolean_expr,
1737                                 Modifiers.PUBLIC | Modifiers.OVERRIDE | Modifiers.DEBUGGER_HIDDEN, new MemberName ("Equals", loc),
1738                                 Mono.CSharp.ParametersCompiled.CreateFullyResolved (new Parameter (null, "obj", 0, null, loc), TypeManager.object_type), null);
1739
1740                         Method tostring = new Method (this, null, TypeManager.system_string_expr,
1741                                 Modifiers.PUBLIC | Modifiers.OVERRIDE | Modifiers.DEBUGGER_HIDDEN, new MemberName ("ToString", loc),
1742                                 Mono.CSharp.ParametersCompiled.EmptyReadOnlyParameters, null);
1743
1744                         ToplevelBlock equals_block = new ToplevelBlock (equals.Parameters, loc);
1745                         TypeExpr current_type;
1746                         if (IsGeneric)
1747                                 current_type = new GenericTypeExpr (this, loc);
1748                         else
1749                                 current_type = new TypeExpression (TypeBuilder, loc);
1750
1751                         equals_block.AddVariable (current_type, "other", loc);
1752                         LocalVariableReference other_variable = new LocalVariableReference (equals_block, "other", loc);
1753
1754                         MemberAccess system_collections_generic = new MemberAccess (new MemberAccess (
1755                                 new QualifiedAliasMember ("global", "System", loc), "Collections", loc), "Generic", loc);
1756
1757                         Expression rs_equals = null;
1758                         Expression string_concat = new StringConstant ("{", loc);
1759                         Expression rs_hashcode = new IntConstant (-2128831035, loc);
1760                         for (int i = 0; i < parameters.Count; ++i) {
1761                                 AnonymousTypeParameter p = (AnonymousTypeParameter) parameters [i];
1762                                 Field f = (Field) Fields [i];
1763
1764                                 MemberAccess equality_comparer = new MemberAccess (new MemberAccess (
1765                                         system_collections_generic, "EqualityComparer",
1766                                                 new TypeArguments (new SimpleName (TypeParameters [i].Name, loc)), loc),
1767                                                 "Default", loc);
1768
1769                                 Arguments arguments_equal = new Arguments (2);
1770                                 arguments_equal.Add (new Argument (new MemberAccess (new This (f.Location), f.Name)));
1771                                 arguments_equal.Add (new Argument (new MemberAccess (other_variable, f.Name)));
1772
1773                                 Expression field_equal = new Invocation (new MemberAccess (equality_comparer,
1774                                         "Equals", loc), arguments_equal);
1775
1776                                 Arguments arguments_hashcode = new Arguments (1);
1777                                 arguments_hashcode.Add (new Argument (new MemberAccess (new This (f.Location), f.Name)));
1778                                 Expression field_hashcode = new Invocation (new MemberAccess (equality_comparer,
1779                                         "GetHashCode", loc), arguments_hashcode);
1780
1781                                 IntConstant FNV_prime = new IntConstant (16777619, loc);
1782                                 rs_hashcode = new Binary (Binary.Operator.Multiply,
1783                                         new Binary (Binary.Operator.ExclusiveOr, rs_hashcode, field_hashcode),
1784                                         FNV_prime);
1785
1786                                 Expression field_to_string = new Conditional (new Binary (Binary.Operator.Inequality,
1787                                         new MemberAccess (new This (f.Location), f.Name), new NullLiteral (loc)),
1788                                         new Invocation (new MemberAccess (
1789                                                 new MemberAccess (new This (f.Location), f.Name), "ToString"), null),
1790                                         new StringConstant (string.Empty, loc));
1791
1792                                 if (rs_equals == null) {
1793                                         rs_equals = field_equal;
1794                                         string_concat = new Binary (Binary.Operator.Addition,
1795                                                 string_concat,
1796                                                 new Binary (Binary.Operator.Addition,
1797                                                         new StringConstant (" " + p.Name + " = ", loc),
1798                                                         field_to_string));
1799                                         continue;
1800                                 }
1801
1802                                 //
1803                                 // Implementation of ToString () body using string concatenation
1804                                 //
1805                                 string_concat = new Binary (Binary.Operator.Addition,
1806                                         new Binary (Binary.Operator.Addition,
1807                                                 string_concat,
1808                                                 new StringConstant (", " + p.Name + " = ", loc)),
1809                                         field_to_string);
1810
1811                                 rs_equals = new Binary (Binary.Operator.LogicalAnd, rs_equals, field_equal);
1812                         }
1813
1814                         string_concat = new Binary (Binary.Operator.Addition,
1815                                 string_concat,
1816                                 new StringConstant (" }", loc));
1817
1818                         //
1819                         // Equals (object obj) override
1820                         //
1821                         LocalVariableReference other_variable_assign = new LocalVariableReference (equals_block, "other", loc);
1822                         equals_block.AddStatement (new StatementExpression (
1823                                 new SimpleAssign (other_variable_assign,
1824                                         new As (equals_block.GetParameterReference ("obj", loc),
1825                                                 current_type, loc), loc)));
1826
1827                         Expression equals_test = new Binary (Binary.Operator.Inequality, other_variable, new NullLiteral (loc));
1828                         if (rs_equals != null)
1829                                 equals_test = new Binary (Binary.Operator.LogicalAnd, equals_test, rs_equals);
1830                         equals_block.AddStatement (new Return (equals_test, loc));
1831
1832                         equals.Block = equals_block;
1833                         equals.Define ();
1834                         AddMethod (equals);
1835
1836                         //
1837                         // GetHashCode () override
1838                         //
1839                         Method hashcode = new Method (this, null, TypeManager.system_int32_expr,
1840                                 Modifiers.PUBLIC | Modifiers.OVERRIDE | Modifiers.DEBUGGER_HIDDEN,
1841                                 new MemberName ("GetHashCode", loc),
1842                                 Mono.CSharp.ParametersCompiled.EmptyReadOnlyParameters, null);
1843
1844                         //
1845                         // Modified FNV with good avalanche behavior and uniform
1846                         // distribution with larger hash sizes.
1847                         //
1848                         // const int FNV_prime = 16777619;
1849                         // int hash = (int) 2166136261;
1850                         // foreach (int d in data)
1851                         //     hash = (hash ^ d) * FNV_prime;
1852                         // hash += hash << 13;
1853                         // hash ^= hash >> 7;
1854                         // hash += hash << 3;
1855                         // hash ^= hash >> 17;
1856                         // hash += hash << 5;
1857
1858                         ToplevelBlock hashcode_top = new ToplevelBlock (loc);
1859                         Block hashcode_block = new Block (hashcode_top);
1860                         hashcode_top.AddStatement (new Unchecked (hashcode_block));
1861
1862                         hashcode_block.AddVariable (TypeManager.system_int32_expr, "hash", loc);
1863                         LocalVariableReference hash_variable = new LocalVariableReference (hashcode_block, "hash", loc);
1864                         LocalVariableReference hash_variable_assign = new LocalVariableReference (hashcode_block, "hash", loc);
1865                         hashcode_block.AddStatement (new StatementExpression (
1866                                 new SimpleAssign (hash_variable_assign, rs_hashcode)));
1867
1868                         hashcode_block.AddStatement (new StatementExpression (
1869                                 new CompoundAssign (Binary.Operator.Addition, hash_variable,
1870                                         new Binary (Binary.Operator.LeftShift, hash_variable, new IntConstant (13, loc)))));
1871                         hashcode_block.AddStatement (new StatementExpression (
1872                                 new CompoundAssign (Binary.Operator.ExclusiveOr, hash_variable,
1873                                         new Binary (Binary.Operator.RightShift, hash_variable, new IntConstant (7, loc)))));
1874                         hashcode_block.AddStatement (new StatementExpression (
1875                                 new CompoundAssign (Binary.Operator.Addition, hash_variable,
1876                                         new Binary (Binary.Operator.LeftShift, hash_variable, new IntConstant (3, loc)))));
1877                         hashcode_block.AddStatement (new StatementExpression (
1878                                 new CompoundAssign (Binary.Operator.ExclusiveOr, hash_variable,
1879                                         new Binary (Binary.Operator.RightShift, hash_variable, new IntConstant (17, loc)))));
1880                         hashcode_block.AddStatement (new StatementExpression (
1881                                 new CompoundAssign (Binary.Operator.Addition, hash_variable,
1882                                         new Binary (Binary.Operator.LeftShift, hash_variable, new IntConstant (5, loc)))));
1883
1884                         hashcode_block.AddStatement (new Return (hash_variable, loc));
1885                         hashcode.Block = hashcode_top;
1886                         hashcode.Define ();
1887                         AddMethod (hashcode);
1888
1889                         //
1890                         // ToString () override
1891                         //
1892
1893                         ToplevelBlock tostring_block = new ToplevelBlock (loc);
1894                         tostring_block.AddStatement (new Return (string_concat, loc));
1895                         tostring.Block = tostring_block;
1896                         tostring.Define ();
1897                         AddMethod (tostring);
1898                 }
1899
1900                 public override bool Define ()
1901                 {
1902                         if (!base.Define ())
1903                                 return false;
1904
1905                         DefineOverrides ();
1906                         return true;
1907                 }
1908
1909                 public override string GetSignatureForError ()
1910                 {
1911                         return SignatureForError;
1912                 }
1913
1914                 public ArrayList Parameters {
1915                         get {
1916                                 return parameters;
1917                         }
1918                 }
1919         }
1920 }